METHODS AND APPARATUS FOR FLOW-CONTROLLABLE MULTI-STAGED QUEUES

• US 20100061239A1
• Filed: 09/30/2008
• Published: 03/11/2010
• Est. Priority Date: 09/11/2008
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Godbole, Avanindra, Frailong, Jean-Marc, Sindhu, Pradeep
• Granted Patent: US 8,218,442 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/26 using explicit feedback to the source, e.g. choke packets
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 47/266 Stopping or restarting the source, e.g. X-on or X-off
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 47/60 implementing hierarchical scheduling
• CPC Class Codes: H04L 49/505 Corrective measures
• CPC Class Codes: H04L 49/90 Buffering arrangements

Abstract

In one embodiment, a method includes sending a first flow control signal to a first stage of transmit queues when a receive queue is in a congestion state. The method also includes sending a second flow control signal to a second stage of transmit queues different from the first stage of transmit queues when the receive queue is in the congestion state.

Claims

1. An apparatus comprising:

a first flow control module configured to define a first flow control signal based on data flow within a first flow control loop including a physical link, a first stage of queues, and a second stage of queues disposed within the transmission path between the physical link and the first stage of queues; and

a second flow control module configured to define a second flow control signal based on data flow within a second flow control loop including the second stage of queues and excluding the first stage of queues.

2. The apparatus of claim 1, wherein the second flow control loop is a priority-based flow control loop.

3. The apparatus of claim 1, further comprising:

a third flow control module configured to define a third flow control signal based on data flow associated with a third flow control loop including the physical link, the third flow control loop excluding the first stage of queues and the second stage of queues.

4. A method, comprising:

sending a first flow control signal to a first stage of transmit queues when a receive queue is in a congestion state; and

sending a second flow control signal to a second stage of transmit queues different from the first stage of transmit queues when the receive queue is in the congestion state.

5. The method of claim 4, wherein the first stage of transmit queues includes a plurality of transmit queues that fan into a queue included in the second stage of transmit queues.

6. The method of claim 4, wherein the first stage of transmit queues includes a plurality of transmit queues that fan into a plurality of transmit queues included in the second stage of transmit queues.

7. The method of claim 4, wherein the second flow control signal is defined based on a priority associated with a portion of the second stage of transmit queues.

8. The method of claim 4, wherein the congestion state associated with the sending the first flow control signal is defined at a first time, the congestion state associated with the sending the second flow control signal is defined at a second time different than the first time.

9. The method of claim 4, wherein the congestion state associated with the sending the first flow control signal is defined at a time, the congestion state associated with the sending the second flow control signal is defined at the time.

10. The method of claim 4, wherein the sending the first flow control signal and the sending the second flow control signal are triggered in response to the receive queue changing from an available state to a congestion state.